JavaEE, JavaFX and RFID - Part 2: Reading RFID from Java

package org.jugvale.rfid;

import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.util.Collections; import java.util.List; import java.util.Scanner; import java.util.stream.Collectors;

/** * Will read the file created by FTDI when a compatible chip is connected to a * Linux machine using the USB port * * @author william * */ public class LinuxFTDISerialReader { private static final String DEFAULT_DEVICE_BASE_PATH = "/dev/serial/by-id"; private String deviceBasePath; public static final String DEFAULT_ERROR_MESSAGE = "Device not found. Check if a device is connected, the driver FTDI was correctly installed and if the device base Path is right(default is " + DEFAULT_DEVICE_BASE_PATH + ")";

public LinuxFTDISerialReader() { deviceBasePath = DEFAULT_DEVICE_BASE_PATH; }

public LinuxFTDISerialReader(String deviceBasePath) { this.deviceBasePath = deviceBasePath; }

public List<Path> getAvailableDevices() throws IOException { List<Path> deviceList = Collections.emptyList(); try { deviceList = Files.list(Paths.get(deviceBasePath)).collect( Collectors.toList()); } catch (Exception e) { e.printStackTrace(); throw new IOException(DEFAULT_ERROR_MESSAGE, e); } return deviceList; }

/** * Will lock the thread reading the device. Should be executed in a * separated thread! * * @param device * @return * @throws IOException */ public String waitAndRead(Path device) throws IOException { if (device == null || !Files.exists(device)) { throw new IOException("Device should not be null!"); } Scanner scanner = new Scanner(device); String rfid = null; while (scanner.hasNextLine()) { rfid = scanner.nextLine(); if (rfid != null && !rfid.trim().isEmpty()) break; } scanner.close(); return rfid.substring(1); } }

package org.jugvale.rfid.ui;

import java.io.IOException; import java.nio.file.Path; import java.util.concurrent.ExecutionException; import java.util.function.Consumer;

import javafx.concurrent.Task; import javafx.scene.control.Label; import javafx.scene.control.ListView; import javafx.scene.control.TitledPane; import javafx.scene.input.MouseEvent; import javafx.scene.layout.StackPane;

import org.jugvale.rfid.LinuxFTDISerialReader;

/** * @author william * */ public class FTDIReaderPane extends TitledPane {

LinuxFTDISerialReader reader = new LinuxFTDISerialReader(); ListView<Path> listDevices; /** * To be invoked when we read the RFID */ Consumer<String> onRead; Consumer<String> onError;

private Path selectedDevice;

public FTDIReaderPane() { this(null, null); } public FTDIReaderPane(Consumer<String> onRead, Consumer<String> onError) { super(); this.onRead = onRead; this.onError = onError; settings(); initComponent(); }

public void setOnRead(Consumer<String> onRead) { this.onRead = onRead; }

public void setOnError(Consumer<String> onError) { this.onError = onError; }

/** * * Will show up and read a RFID tag, but it will always ask to select a tag * * @throws IOException * Error when it can't read the device */ public void askForDeviceAndReadTag() { try { if (selectedDevice == null) fillDevices(); else { readDevice(); } setVisible(true); } catch (Exception e) { e.printStackTrace(); fail(LinuxFTDISerialReader.DEFAULT_ERROR_MESSAGE); } }

private void settings() { setText("Read RFID Tag"); setMaxHeight(200); setMaxWidth(300); setStyle("-fx-stroke-width: 20;"); setCollapsible(false); setVisible(false); }

private void initComponent() { StackPane root = new StackPane(); Label lblPassCard = new Label("Pass RFID Card"); lblPassCard.setStyle("-fx-font-size: 20px; -fx-font-weight: bold"); listDevices = new ListView<>(); listDevices.setOnMouseReleased(this::newDeviceSelectedAction); root.getChildren().addAll(listDevices, lblPassCard); lblPassCard.visibleProperty().bind(listDevices.visibleProperty().not()); this.setContent(root); }

private void newDeviceSelectedAction(MouseEvent e) { Path selectedPath = listDevices.getSelectionModel().getSelectedItem(); if (selectedPath != null) { listDevices.setVisible(false); listDevices.getSelectionModel().clearSelection(); selectedDevice = selectedPath; readDevice(); return; } }

private void fillDevices() throws IOException { listDevices.setVisible(true); listDevices.getItems().setAll(reader.getAvailableDevices()); listDevices.getSelectionModel().clearSelection(); }

private void readDevice() { new Thread(new Task<String>() { @Override protected String call() throws Exception { return reader.waitAndRead(selectedDevice); }

@Override protected void succeeded() { try { success(this.get()); } catch (InterruptedException | ExecutionException e) { e.printStackTrace(); } setVisible(false); }

@Override protected void failed() { fail(LinuxFTDISerialReader.DEFAULT_ERROR_MESSAGE); setVisible(false); selectedDevice = null; } }).start(); } private void success(String value) { if(onRead == null) { throw new Error("You must set an onRead funcion"); } onRead.accept(value); } private void fail(String value) { if(onError == null) { throw new Error("You must set an onError funcion"); } onError.accept(value); } }